How can I create a polygon using fields in PostgreSQL?

Question

I have 8 real values in a table that I\'d like to combine into a polygon. I haven\'t been able to figure out how to create a polygon using these values though. I keep trying

Answer 1

This example takes longitude and latitude coordinates from a table and converts them into a geometry. The dimensions of each box are given as long_high, long_low, lat_high, and lat_low. Here, a box of approximately 500m by 500m.

1. Add a new geometry column 'box' to the table

   SELECT AddGeometryColumn('public', 'predpol_raw', 'box', 2240, 'POLYGON', 2);

2. Update the new field with those values.

   UPDATE predpol_raw
   SET box =
           ST_Transform(
               ST_GeomFromText(
                   format('POLYGON((%s %s, %s %s, %s %s, %s %s, %s %s))',
                       long_high,lat_high, long_low,lat_high,
                       long_low,lat_low, long_high,lat_low,
                       long_high,lat_high
                   ),
                   4326
               ),
               2240
           );
   

Note the transformation to a different spatial reference. The POLYGON keyword requires double parentheses '(( ))'.